As communities across the nation grapple with housing affordability, several companies are figuring out how to use 3D printers to provide less expensive homes. Green, clean, and efficient 3D homes are popping up across the country. They're printed in place, layer by layer, using concrete blends. Building a 3D home requires less labor and reduces waste on the job site. Habitat for Humanity Peninsula & Greater Williamsburg in Newport News, Virginia, has completed and sold three 3D-printed homes, C